CAIRO, July 2 (Reuters) - Egyptian President Mohamed Mursi called on the armed forces on Tuesday to withdraw an ultimatum for him to share power with his political opponents and said he would not be dictated to.

"President Mohamed Mursi asserts his grasp on constitutional legitimacy and rejects any attempt to deviate from it, and calls on the armed forces to withdraw their warning and refuses to be dicatated to internally or externally," a tweet on the official Twitter feed of the Egyptian presidency said.

A military source said the armed forces had seen Mursi's statement and would issue a response to it. (Reporting by Ahmed Tolba and Asma Alsharif; Editing by Alastair Macdonald)